How to emulate near in the Twitter Search API using GeoPlanet

Twitter's Search API is fantastic, but unlike the UI version they don't support using the name of a place to limit your results, only latitude and longitude. I couldn't ask my users to type in coordinates for searches, so I needed some way to translate the names into the form Twitter wants.

The process of converting from human names into coordinates is known as geocoding, and luckily there's some great free web APIs that will do the job for you. I chose Yahoo's GeoPlanet, they allow up 50,000 requests a month, and Tyler Hall has a great PHP wrapper ready to use.

I couldn't find a good example of actually using GeoPlanet in PHP, so I decided to kill two birds with one stone and publish my code as sample code for geocoding, and offer an off-the-shelf solution for anyone else who needs 'near' for Twitter searching. You can download geosearch.php
, and it's included below.